Berrettini wins in Kitzbuhel for second successive title at expense of Gaston
It marked a tenth ATP career title for the Italian who has already won this year in Gstaad, Marrakech and last week in Switzerland.
The former world no.6, who had slipped to 154 in the world in April, is now set to rise to 40 in the new ATP rankings.
Gaston was playing his second final on the ATP circuit and looking for his first title. In Gstaad in 2021, he lost his only previous final to the Norwegian Casper Ruud.
Berrettini said he was "so happy and so tired" after the final.
"Fortunately I had a double break lead in the second. I was hitting well, I was playing aggressively," he added.
"But Hugo made my life complicated and I'm happy to end up with the victory."